Gauze brush.



E. SCHWEHZER.

y GAUZE musa, APPLICATION FILED MAH. l1, 19W.

L4-'Patented June 5, 1917.

eXpensive to manufacture and require careful seating upon the commutating surface, due to their rigidity. Tln` increased conductivity in a 'transverse direction also entails difficulty from short circuit current.

But -through all these developments, the

' gauze brush, that is a brush made of woven wire screen or cloth has been extensively employed. This brush still persists in use for many classes of services in spite of the many new types of brushes. such as the Bronskol, Metite, metalloid, etc.,`which are made of a composition of graphite. carbon, copper. tin. etc., which are combined into a solid to form an alloy-lille material.

The reason that the gauze brushes continue to'be employed for the collection of current from commutators and collector' rings is because they embody a large number of desirable qualities. such as relatively long life, relatively high carrying capacity, high transverse resistance, etc.

The gauze brush also causes less abrasion than the ordinary copper leaf brush unless the latter has been formed very expertly to the surface of the commutator or collector ring from which the current is collected.

Gauze brushes usually are made by rolling the gauze in sheets upon a 'suitable mandrel or arbor mounted in a machine adapted for the purpose. After the screen has been wound upon the mandrel to the desired dimension, the gauze is removed from the mandrel and is pressed in a suitable die to the desired form and dimension. One end is then usually soldered to hold the gauze in a permanent form. The electrical performance of gauze brushes can be made superior to that of the previously descr`1bed brushes for heavy current service. However, with respect to mechanical perfornianee, the ygauze brush has failed to compete successfully with 'the more recently developed carbon, graphite. metal combination of brushes. such as are known by the tradenames of Bronskol Broucekohl, Metite and similar material. This shortcoming lies in the fact that the gauze brush will cut the connnutator or collector rings excessively or will itself be excessively worn by the abrasion of those slufaces.V

My invention aims to provide a gauze brush which is so constructed that the abrasive tendency is greatly reduced, if not entirely eliminated, so that less wear, both upon the brush itself and upon the commutating surface is entailed.

The manner in which l practise my invention will now be set forth in detail, particular reference being made to the appended drawings which form a part of the present specification.

Figure 1 an. isometric view of one form of completed brush constructed in accordance with my invention;

Fig. 2 shows in elevation the wire gauze materiial ,from which the body of the brush is constructed;

Figk shows this material on an enlarged scale in cross section;

Fig. 4 shows a piece of the wire gauze upon which a deposit of other metal has been made, as will be described later;

Fig. 5 is a section similar to Fig. 3 showing the gauze after the deposition of metal thereupon 3 Fig. 6 shows the manner in which the gauze is rolled upon a mandrel;

Fig. 7' illustrates in elevation the rollers which form the brush;

Fig. S illustrates a mandrel for obtaining a different size of brush;

Fig. 9 is a diagram illustrating the electro deposition of the metal upon the brush after the same has been formed.

Fig. 10 showsvthe manner in which the lubricating metal may be deposited by dipping in molten metal;

Fig. 11 shows in cross section the construction of a modilied form of brush;

Fig. 12 illustrates the same in the completed condition; and

Figs. 13 and 14 are diagrams illustrating the action of an individual thread or wire upon which the lubricating metal is deposited.

According to my invention a suitable lubricating metal such as tin, lead and tin, Monel metal, or the like is deposited upon the wire screen in such a manner as to inclose each individual wire with a film or envelop of greater or less thickness of antifriction metal.

The completed brush is preferably formed in the conventional prismatic form as shown in Fig. 1 to be employed in the different types of brush holders. A strip of copper, bronze or brass wire gauze, such as is illustratcd in Fig. 2, is employed as the body of the brush. The brush may be formed and the anti-friction metal deposited upon the gauze after forming, or if preferred, the anti-friction metal may be deposited upon the gauze before the same is formed into brush form. Assuming that the first procedure is to be followed, a strip of the gauzel 2 is wound upon a suitable mandrel 3 until a roll of the required size has been formed. The mandrel 3 is then withdrawn and the roll of gauze is then formed 4either by pressing in dies, or as shown in Fig. (5, by rolling between opposite pairs of rollers 4 and 5 to bring the brush to the required form.

The body of the brush l may then have the anti-friction metal deposited in the in-l terstices of the gauze either by electroplating, as shown in Fig. 9, or by dipping, as shown in Fig. 10. The advantage of electroplating is that any desired l.amount of metal may be depositedln other words.

fil

the quantity control of the deposit renders it possible to determine to a nicety the thickness of the ilm deposited upon the gauze.

F or electroplating the brush l forms the cathode in a suitable electrolyte 6, the an: ode 7 comprising the metal which is to loe `deposited upon tlie gauze of the brush l.

gauze' then rolled into suitable shape for forming the brush.

ln Fig. l l have shown a piece of gauze upon the end of which 9, a deposit of anti friction metal has been made. ln Fig. 5 l have shown a cross sectional ViewT of the saine. lt can loe seen that each individual Wire l0 is surrounded by a lilm or coat olE anti-friction metal li. The brush may be formed in the. saine manner as previously described, that is by rolling upon a mandrel and then forming either by dies or by rollers.

Special forms or brushes may be formed as 'Shown in llifg. S Where the mandrel 3 coniprises a plate l2 for. .obtaining a roll of the gauze 2.

llhere a large bearing euri-ace is required, l have found it advantageous to subdivide the gauze brush into a number of .fliii'erent parts. brushes can he more easil,7 impregnated and can he i'orined more readily and cheaply because the size of the gauze sheet is less and manipulation is easier.

il `gauze brush of excellent performance can also be inode by constructing the saine of a unit consisting` of smaller units, as dei scribed, and then holding the units as shown at 13 in l1 together by ineens olii a sheet of gauze l- Wrapped one or more tir around the aggregate units 13. The units i3 are formed in the usual Way and the gauze Wrapper ist after being: applied is pinned to retain it in position. The end ot thebrush, as shown at l5 in dipped in hard solder to secure the parte together. The body or the brush may then lie electro-plated.

lf the anti-friction metal is to be deposited by dipping.7 hard soldering of the end may be dispensed with or may loe performed after the dipping operation.

The anti-friction metal which surrounds the individual 'Wires operate to decrease the riction of the Contact surface by surroundl2, is

ln this condition7 the.

'the saine as well as the harder bronze ing the cutting' edges of O Wliich ijorin. the

wires tividual Wire such l0 shown in Fi econies adjusted to the coinniutator i6 hat thereafter the position of this Wire is sliii'tec as shown in Fig. lll. lf the coating or anti-friction metal were not present the heel of the Wire would `present a. fairly elia-rp surface and would tend to score the connnutator. lilou@- ever, thev Elin of lubricating etal ll. `prevents the sharp edge trom coming directly in contact with the coinin'utator lo.

The deposite'A anti 'Eviction or lubricating nieta is also beneficial 'i increasing the cross section ano. consequentliT the l for electric current Without inceasing the external dimension ci the brush. urt ier advantage of this treatment lies in the tact that the gauze .lrush thus treated tends to hold its form permanently and Will not bow or fray'out at the edge ci the contact surface as is the euse with the brushes of the 'prior l prefer to use 'the electro-plating method ci' applying the lubricating metal, although dipping the gauze in inolten tin or the like has advantages in case a quicl: deposit of a maximum quzmtit)7 of lubricating material .is desired. ll/There dipping employeda l have found it advisable afterward to nmH nipulate the brush so that the particles of iinpregnating ine-tal will be somewhat disn integrated tlius restoring^ the natural resiliency and flexibility of the gauze brush.

lt is obvious that this principle of lubrication of the individual conductors will apply to copper lea-r brushes or the like.

is apparent l may treat the individual Wires priorto Weaving or fabricating.; them into gauze. li intend the following1 claiis to cover tuemethod of making cover a brush `1- errar.

gauze '.i 1 1 1` interlaced or @sound t What l claim is: l. n a orusli ot the class descri ed.l a corr tafl n coinn'ni lie rel a surface coating of a soft lubricating metal in solid form completely inclosing` the wire,

said coating adhering ,to and moving with the individual wire upon which' it is deposited, said lubricating metal being substantially softer than copper.

3. A brush for dynamos and the like comprising a gauze body portion formed of interlacing wires, said wires having deposited upon theirl individual surfaces a surface film of soft crystalline lubricating metal, said .netal being substantially softer than copper, said brush being substantially free of carbonaceous 'lubricatixl-g material.

4. A brush for electrical. machinery cour prising a body of wire gauze formed into a prismatic block, the wires of said gauze having deposited upon their individual surfaces individual surface coatings of a soft lubricating metal comprising tin. l

A brush for electrical machinery comprising a body of wire gauze, the wire of said gauze being made of copper or an alloy thereof, the individual wires of said gauze having deposited upon their surfaces solid metallic surface ihns of a lubricating metal softer than copper, said films adhering to and moving with the individual wires.

C. A brush for electrical machinery comprising a plurality of sections formed of metallic wire Agauze rolled and compressed into a prismatie form, a wrapper of metallic wire gauze surrounding` said sections and means to hold said wrapper and said sections together, said sections and said wrapper having a surface deposit of a soft lubricating metal formed upon the individual wires thereof, said metal being sub-stantiali y softer than copper.

7. The process of treating wire gauze enr ployed for commutator or collector brushes which consists in depositing upon the individual wires a surface coating of 'tin in solid forni.

8. The process of treating gauze employed foi-.electrical brushes which consists in electrodepositing upon the individual wires of the gauze a surface coating of a soft metal consisting mostly of tin.

9. A brush for dynamos and the like comprising a body of gauze in compressed form, said gauze comprising a plurality of wires formed of a relatively hard metal consisting mainly of copper, lach of said wires having deposited upon its surfaces a complete coating of tin forming a sheet of lubricating material adhering to and movable with the individual wire.

l0. A brush for electrical machinery comprising a body of gauze, said body of gauze comprising a plurality of ii'iterlaced wires having upon their imliviuual surfaces coatings onlyy of a metal con'iprising tin, the interstices between said wires being open.

ll. A brush for electrical contact with a metallic surface comprising a plurality of tine wires interwoven into a gauze, each of said wires having an individual coating thereon of metal softer than that of the wires and that of the contact surface whereby to provide a luln'icating lihn between the wires and said surface.

l2. A brush formed of interwoven metal wires havingl each an individual metalcoat'- ing onlyof a metal softeifthan copper to afford lubricating means for the same.

n witness whereof, I hereunto subscribe my name this 15th day of March, A. D. 1916.

.EDMUND O. SCIflWE-IlZER. 

